Caption: This image of the supernova RCW 86 combines X-ray data from Chandra and XMM-Newton (blue and green) along with infrared data from Spitzer and WISE (yellow and red). Astronomers used these data to determine that a Type Ia supernova explosion, which was witnessed nearly 2,000 years ago by Chinese astronomers, was the source of the RCW 86 remnant seen today. Type Ia supernovas are created when an otherwise stable white dwarf is pushed beyond the brink of stability when a companion star dumps material onto it.